package com.hnevc.xiewenguang;

    import java.util.Scanner;

    public class Example01 {
        public static void main(String[] args) {
            double pi = 3.1415927;
            Scanner sc = new Scanner(System.in);
            int r = sc.nextInt();
            double v;
            v = (4 * pi * r * r * r) / 3;
            System.out.printf("%.3f", v);
        }
    }
